1ꢀFerrocenylisoquinoline palladacycle
Russ.Chem.Bull., Int.Ed., Vol. 64, No. 1, January, 2015
149
C(7), C(6*), C(7*)); 136.7 and 136.9 (4 C, C(4a), C(4a*));
142.5 (2 C, C(3)); 143.2 (2 C, C(3*)); 167.7 and 168.4 (4 C,
C(1), C(1*)).
Experimental
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For compounds 4—6, H and 13C NMR spectra were reꢀ
(Triphenylphosphine)[2ꢀ(1ꢀisoquinolinyl)ferrocenyl](C,N)ꢀ
palladium chloride (6). Triphenylphosphine (0.0367 g, 0.140 mmol)
was added to a solution of 5 (0.0578 g, 0.128 mmol) in CH2Cl2
(30 mL). The mixture was stirred for 2 h, concentrated, and
subjected to chromatography on Al2O3 (light petroleum—AcOEt,
100 : 0—75 : 25—0 : 100) to obtain complex 6 (0.0523 g, 57%).
Found (%): C, 61.81; H, 4.24; N, 1.81. C37H29ClFeNPPd. Calꢀ
corded at 600.22 and 150.93 MHz, respectively, on a Bruker
AvanceTM 600 spectrometer equipped with an inverse gradient
probeꢀhead. 1D and 2D experiments (COSY, ROESY, HMQC, and
HMBC) were carried out at 25 C using a standard pulse seꢀ
quences from the Bruker library. For other compounds, 1H NMR
spectra were obtained on a Bruker Avance 300. Chemical shifts
in the NMR spectra of solutions in CD3CN and CDCl3 were
determined relative to the signals of residual protons (1H NMR
spectra) or relative to the signal of the solvent (13C NMR spectra)
and recalculated to SiMe4. The H and C atoms numbering sysꢀ
tem is given in Scheme 1. Bromoferrocene (3) was synthesized
according to the known procedure.13
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culated (%): C, 62.04; H, 4.08; N, 1.96. H NMR (CDCl3),
: 3.70 (s, 5 H, C5H5); 3.58 (br.s, 1 H, H(5´)); 4.29 (br.s, 1 H,
H(4´)); 5.12 (br.s, 1 H, H(3´)); 7.64 (pt, 1 H, H(7)); 7.74 (pt, 1 H,
3
H(6)); 8.48 (d, 1 H, H(8), J (1H,1H) = 8.0 Hz); 7.43—7.49
(m, 11 H, H(4) and mꢀ and pꢀPh); 7.85—7.90 (m, 7 H, H(5) and
oꢀPh); 9.43 (dd, 1 H, H(3), 3J (1H,1H) = 8.0 Hz, 4J (1H,31P) =
= 3.0 Hz). 13C NMR (CDCl3), : 69.7 (d, 1 C, C(5´),
3J (13C,31P) = 4.5 Hz); 70.7 (s, 5 C, C5H5); 76.4 (d, 1 C, C(4´),
4J (13C, 31P) = 9.0 Hz); 89.0 (s, 1 C, C(3´)); 103.3 (s, 1 C, C(2´));
1ꢀFerrocenylisoquinoline (4) (see Ref. 6). A 2.5 M solution of
BuLi in hexane (3.2 mL, 8 mmol) was added to a solution of
bromoferrocene (2 g, 7.5 mmol) in diethyl ether (40 mL) at
–10 C, the mixture was stirred at room temperature for 30 min.
A solution of isoquinoline (0.97 g, 7.5 mmol) in diethyl ether
(20 mL) was added to the obtained orange suspension of ferroꢀ
cenyllithium, the mixture was stirred for 30 min, followed by the
addition of a solution of DDQ (1.7 g, 7.5 mmol) in THF (20 mL)
and stirring for 30 min. Then the mixture was passed through
celite, the celite washed with diethyl ether, the solvent was evapꢀ
orated, the residue was subjected to chromatography on SiO2
(light petroleum : AcOEt = 100 : 0 – 80 : 20) to obtain comꢀ
pound 4 (0.88 g, 38%). 1H NMR (CD3CN), : 4.2 (s, 5 H,
2
117.5 (d, 1 C, C(1´), J (13C, 31P) = 1.5 Hz); 124.6 (d, 1 C,
C(8a), 4J (13C, 31P) = 3.0 Hz); 126.3 (s, 1 C, C(8)); 127.4 (s, 1 C,
C(7)); 127.6 (s, 1 C, C(5)); 128.2 (d, 6 C, CPhꢀm, 3J (13C, 31P) =
= 10.5 Hz); 130.4 (d, 3 C, CPhꢀp, 4J (13C, 31P) = 3.0 Hz); 131.2
1
(s, 1 C, C(6)); 132.1 (d, 3 C, CPhꢀipso, J (13C, 31P) = 49.5 Hz);
134.9 (d, 6 C, CPhꢀo, 2J (13C, 31P) = 12.0 Hz); 137.3 (s, 1 C, C(4a));
142.7 (s, 1 C, C(3)); 166.6 (s, 1 C, C(1)).
Reaction of cyclopalladate 5 with ethyl acrylate. A solution of
dimer 5 (0.3 g, 0.66 mmol), ethyl acrylate (0.1 mL, 0.92 mmol),
and triethylamine (0.14 mL, 0.99 mmol) in toluene (10 mL) was
refluxed for 9 h, filtered, the filtrate was washed with water
and aqueous NaHCO3, dried with Na2SO4, concentrated,
and subjected to chromatography on SiO2 (hexane—AcOEt,
100 : 0—50 : 50). The collected fractions were concentrated to
obtain compound 4 (0.14 g, 67%).
3
C5H5); 4.52 (t, 2 H, H(3´), H(4´), J = 1.8 Hz); 5.02 (t, 2 H,
H(2´), H(5´), 3J = 1.8 Hz); 7.54 (d, 1 H, H(4), 3J = 5.6 Hz); 7.63
(pseudo triplet (pt), 1 H, H(7)); 7.67 (pt, 1 H, H(6)); 7.85 (d, 1 H,
3
H(5)); 8.48 (d, 1 H, H(3), J = 5.6 Hz); 9.00 (d, 1 H, H(8),
3J = 8.4 Hz). 13C NMR (CD3CN), : 69.6 (2 C, C(3´), C(4´));
69.8 (5 C, C5H5); 70.8 (2 C, C(2´), C(5´)); 84.9 (1 C, C(1));
118.9 (1 C, C(4)); 126.4 (1 C, C(7)); 126.8 (1 C, C(8a)); 127.3
(2 C, C(5), C(8)); 129.6 (1 C, C(6)); 136.8 (1 C, C(4a)); 142.0 (1 C,
C(3)); 159.2 (1 C, C(1)).
4ꢀPhenylacetophenone (10) (Suzuki reaction). A. Phenylboꢀ
ronic acid (0.183 g, 1.5 mmol), 4ꢀbromoacetophenone (9b)
(0.183 g, 1 mmol), and K2CO3 (0.276 g, 2 mmol) were added to
a mixture of MeOH (4 mL) and water (2 mL) with stirring,
which was stirred for 5 min, followed by the addition of 5
(0.5 mol.%). The reaction mixture was stirred at room temperaꢀ
ture for 5 h, diluted with water, extracted with chloroform, dried
with Na2SO4, concentrated, and subjected to chromatography
on SiO2 (hexane—CHCl3, 1 : 1) to obtain compound 10 (0.189 g,
Diꢀꢀchloroꢀbis[2ꢀ(1ꢀisoquinolinyl)ferrocenyl](C,N)dipalꢀ
ladium (5). A solution of 4 (0.60 g, 1.9 mmol) was added to
a solution of Na2PdCl4 (0.56 g, 1.9 mmol) and AcONa•3H2O
(0.26 g, 1.9 mmol) in MeOH (30 mL), the mixture was stirred for
6 h. A precipitate formed was filtered off, washed with MeOH
and diethyl ether, and subjected to chromatography on Al2O3
(AcOEt, then CH2Cl2—MeOH, 9 : 1). The residue after evapoꢀ
ration of the solvents was subjected to chromatography on SiO2
(light petroleum—AcOEt, 5 : 5—0 : 10) to obtain palladacycle 5
(0.56 g, 64%). Found (%): C, 50.39; H, 3.27; N, 3.04.
C19H14ClFeNPd. Calculated (%): C, 50.26; H, 3.11; N, 3.08.
1H NMR (CD3CN), : 4.12, 4.18 (both br.s, 10 H, C5H5); 4.58,
4.64 (both br.s, 4 H, H(4´), H(4´*)); 4.80 and 4.95, 5.18 and 5.23
(all br.s, 8 H, H(3´), H(5´), H(3´*), H(5´*)); 7.55, 7.58 (both d,
4 H, H(4), H(4*), 3J = 6.6 Hz); 7.75 (pt, 4 H, H(7), H(7*)); 7.85
(pt, 4 H, H(6), H(6*)); 7.96 (m, 4 H, H(5), H(5*)); 8.48 (m, 4 H,
H(8), H(8*)); 8.26 (br.s, 2 H, H(3)); 9.05 (br.s, 2 H, H(3*)).
13C NMR (CD3CN), : 68.0 and 68.1, 72.9 and 74.4 (8 C, C(3´),
C(5´), C(3´*), C(5´*)); 70.0 and 70.3 (4 C, C(4´), C(4´*)); 70.7
(10 C, C5H5); 87.3 and 87.7 (4 C, C(2´), C(2´*)); 101.0 (4 C,
C(1´), C(1´*)); 117.8 and 118.4 (4 C, C(4), C(4*)); 124.7 and
124.8 (4 C, C(8a), C(8a*)); 126.6 and 127.3 (8 C, C(5), C(8),
C(5*), C(8*)); 128.2 and 128.3, 131.9 and 132.1 (8 C, C(6),
1
97%), whose H NMR spectrum corresponded to that given in
the literature.14
B. A mixture of phenylboronic acid (0.1829 g, 1.5 mmol),
4ꢀbromoacetophenone (9b) (0.1488 g, 0.81 mmol), ground K2CO3
(1.38 g, 10 mmol), and catalyst 5 (0.0023 g, 0.5 mol.%) was
stirred with a glass rod until a uniform mass was formed and
was allowed to stand for 1 week in a capped flask, periodicalꢀ
ly stirring. By this time, the reaction mixture became a solid
conglomerate, to which a ground K2CO3 (1.38 g, 10 mmol)
was added, the resulting mixture was stirred with a glass rod
until a uniform mass was formed and was allowed to stand
for 2 weeks in a capped flask, periodically stirring. Then,
the mixture was diluted with CH2Cl2, filtered through celite,
which was washed with CH2Cl2, the solvent was evaporated,
the residue was subjected to chromatography on SiO2 (hexꢀ
ane—CHCl3, 1 : 1) to obtain compound 10 (0.124 g, 85%),
whose 1H NMR spectrum corresponded to that given in the
literature.14